A detailed kinetic investigation in two areas of biochemistry is to be carried out. These are: the kinetic role of metal ions in enzymatic systems and the dynamics of the helix-coil transition in polypeptides. The specific research to be accomplished involves the thermodynamics and kinetics of divalent metal ion interactions with nucleotide, dinucleotide, and flavin coenzymes; the kinetics of metal ion associations with enzymes and enzyme-coenzyme systems; and kinetic studies of the helix-to-coil transition in homo and co-polymeric polyamino acids. The long-term objectives of the research are: l. to elucidate the mechanisms of action of enzymes by studying the rapid elementary steps which constitute the total reactions; 2. to establish the kinetic roles of labile metal ions in enzymatic systems; and 3. to characterize the rates of the helix-coil transition in aqueous polypeptides and to correlate these rates with known properties. A wide variety of rapid kinetic instrumentation will be brought to bear upon these problems. Methods to be used will include rapid stopped flow as well as relaxation spectroscopy (especially T-jump and ultrasonics).